PROJECT SUMMARY Recent advances in developmental neuroscience suggest that experiences early in life have profound and enduring influences on the developing brain. Family economic resources shape the nature of many of these experiences, yet the extent to which they affect children's development is unknown. Our team of neuroscientists, economists and developmental psychologists proposes to fill important gaps in scientific knowledge about the role of economic resources in early development by evaluating the first randomized controlled trial to determine whether unconditional cash payments have a causal effect on the cognitive, socio- emotional and brain development of infants and toddlers in low-income U.S. families. Specifically, 1,000 mothers of infants with incomes below the federal poverty line from four diverse U.S. communities will receive monthly cash payments by debit card for the first 40 months of the child's life. Parents in the experimental group will receive $333 per month ($4,000 per year), whereas parents in the control group will receive a nominal monthly payment of $20. In order to understand the impacts of the added income on children's cognitive and behavioral development, we will assess treatment/control group differences at age 3 (and, for a subset of measures, age 2) on measures of cognitive, language, memory, self-regulation and socio-emotional development. Brain circuitry may be sensitive to the effects of early experience even before early behavioral differences can be detected. In order to understand the impacts of added income on children's brain functioning at age 3, we will assess, during a lab visit, treatment/control group differences in measures of brain activity (electroencephalogram [EEG] and event-related potentials [ERP]). To understand how family economic behavior, parenting, and parent stress and well-being change in response to income enhancement, we will assess treatment/control differences in family expenditures, food insecurity, housing and neighborhood quality; family routines and time use; parent stress, mental health and cognition; parenting practices; and child care arrangements at child age 2 and, for a subset of these measures, child age 1. This study will thus provide the first definitive understanding of the extent to which income plays a causal role in determining early child cognitive, socio-emotional and brain development among low-income families.